Biology

Photosynthesis in Plants

1,492 Questions

Photosynthesis is the biological process by which plants convert light energy into chemical energy. This page contains practice questions covering essential topics like chlorophyll, light reactions, and the pathways specific to plants. This material is crucial for medical entrance exams and academic assessments.

Chlorophyll and pigmentsLight reactionsCalvin cycleCAM plantsElectron transportPhotosynthesis factors

Photosynthesis in Plants Questions

Multiple choice

Which type of energy conversion takes place during photosynthesis?

  1. Solar energy to mechanical energy

  2. Solar energy to chemical energy

  3. Wind energy to chemical energy

  4. Chemical energy to mechanical energy
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

During the process of photosynthesis, solar energy is converted into chemical energy and is stored as organic matter.

Multiple choice

The first step in the dark reaction of photosynthesis is

  1. formation of ATP

  2. ionisation of water

  3. attachment of CO2 to a pentose sugar

  4. excitement of an electron of chlorophyll by a photon of light
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The first step in the dark reaction of photosynthesis is carboxylation in which one molecule of CO2 combines with one molecule of ribulose 1, 5-biphosphate (RuBP) to form unstable six carbon compounds. Carboxylation of RuBP is catalysed by the enzyme RuBP carboxylase or Rubisco.

Multiple choice

Which of the following statements about dark reaction are FALSE?

P. Source of energy for dark reaction is ATP synthesised in light reaction. Q. Raw materials of dark reaction are water, ADP and H3PO4. R. Oxygen is by-product of dark reaction and released to atmosphere. S. Dark reaction occurs in stroma of chloroplast.

  1. Only P and Q

  2. Only P and R

  3. Only P and S

  4. Only Q and R

  5. Only R and S
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Water, ADP and H3PO4 are raw materials for light reaction. Raw materials of dark reaction are CO2, NADPH2 and ATP. Oxygen is the by-product of light reaction and is released in the atmosphere.

Multiple choice

2-Carboxy-D-arabinitol 1-phosphate (CA1P) is synthesized by C4 plants like tobacco and beans in the night. Which of the following functions does it perform?

  1. Enhances the rate of photosynthesis

  2. Forms bonds with CO2 and helps in its storage

  3. Inhibits the catalytic activity of RuBisCo

  4. Incorporates more oxygen into RuBP
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

2-Carboxy-D-arabinitol 1-phosphate (CA1P) inhibits the catalytic activity of RuBisCo at night. RuBisCO activase promotes the release of CA1P from the catalytic sites.

Multiple choice

Which is known as an inhibitor of photosynthesis?

  1. Pyruvate reductase

  2. Glycolate oxidase

  3. 2-phosphoglycolate

  4. 3-phosphoglycerate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Phosphoglycolate inhibits certain enzymes involved in photosynthetic carbon fixation. Hence, it is often said to be an 'inhibitor of photosynthesis'.

Multiple choice

Under which condition can C3 cycle not operate in plants?

  1. High CO2

  2. Absence of oxygen

  3. High CO2 and absence of oxygen

  4. Low CO2 and presence of oxygen
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

C3 cycle cannot operate under very low CO2 conditions and oxygen has inhibitory effect on photosynthesis. Thus, C3 cycle cannot operate in presence of oxygen.